What is happening when Selectionchanged Event is triggerd?

[mihalcea-bogdan-daniel]

Hi,
when the user clicks on an object it is highlighted.
My question is:
The highlight color is applied inside the 3DView canvas or
does it change the object's material properties?
If I want to isolate some objects, how do I update the canvas?

P.S. Sorry if this is a silly question but I've been reading docs for a week or so and I am a bit confused.